The invention relates to a method for operating a vehicle having at least one torque transmission device, which when rotating splashes in a fluid, and at least two axles which each have two wheels and with at least one controllable coupling device by means of which the torque transmission device and at least one of the wheels can be selectively coupled or decoupled for torque transmission.
From the published patent document U.S. 2007/0193808 A1 a control method for the drivetrain of a vehicle with a secondary drive axle, which can be decoupled from the drivetrain, is known. According to this reference the secondary drive axle is decoupled from the drivetrain for saving fuel, when the vehicle speed is above a predetermined speed threshold value. When the vehicle speed is below the predetermined speed threshold value the secondary drive axle is connected with the drivetrain in order to enhance the effect of the regenerative braking.
From the published patent document DE 10 2005 024 757 A1 a method for activating and deactivating the all-wheel-drive in emergency vehicles and working machines, which have no longitudinal locks, is known. According to this reference the all-wheel-drive is activated when the vehicle speed falls below a predetermined threshold value and the transmission output torque exceeds a predetermined threshold value. It is further provided that the all-wheel-drive is deactivated when the vehicle speed exceeds a predetermined threshold value or when the transmission output torque falls below a predetermined threshold value.